This invention relates generally to rockdrills, more particularly rockdrills operable by a fluid under pressure. Still more particularly the invention relates to a seal for sealing one or more fluid pressure chambers defined between at least two static components of a rockdrill operable by a fluid under pressure.
In hydraulically operable rockdrills pressure reversals and fluctuations occur to cause reciprocation of the piston in the drill. The seals used to seal the various chambers defined between static components in the rockdrill, such as the drive chamber, the return chamber, the cushion chamber, etc., when subjected to these pressure reversals can cause the seals to move or dither in their respective grooves. Such movement results in wear of the parts contacted by the seals and failure of the rockdrill. This wear is aggravated when the operating fluid is contaminated with fine abrasive particles. This is often the case in an underground mining environment were handheld hydraulic drills using emulsion fluids or plain water as an operating fluid are being used. The frequent disconnection and reconnection of drills from the pressure source which are necessary when removing drills from the rock face during blasting operations, as well as the reticulation piping extensions as the mine face moves further away from the pressure source, are known sources of contaminant ingress. The abrasive particles are very often too small to be removed from the system by filters.
Seals presently known in the art consist of 0-ring seals or square section seals or crush type seals which are seated in seal grooves of rectangular cross-section. Many of these seals rely on filling the seal groove completely to be effective. This is difficult to achieve due to the size variations resulting from tolerance effects during manufacture.
It is an object of the invention to overcome or at least to alleviate the disadvantages of seals in accordance with the presently known art, more particularly, to overcome dithering of seals in seal grooves.
The foregoing illustrates limitations known to exist in present hydraulic rockdrills. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.